The present disclosure relates generally to oral compositions and methods for inhibiting the formation of plaque biofilm by salivary bacteria, and more particularly, to oral compositions comprising a combination of magnolia bark extract (MBE) and L-arginine, Nα-lauroyl ethyl ester (LAE). The oral compositions are useful for improving oral health, including inhibiting the formation of plaque biofilm and reducing plaque formation and adherence to teeth.
The oral cavity is comprised of more than 700 bacterial species (Aas, et al., “Defining the normal bacterial flora of the oral cavity,” J. Clin. Microbiol., 2005, Vol. 43(11), pp. 5721-32) that live together in symbiosis at times of good oral health (Zarco, et al., “The oral microbiome in health and disease and the potential impact on personalized dental medicine,” Oral. Dis., 2012, Vol. 18(2), pp. 109-20). An ecological shift in the oral microbiome, due to various extrinsic or intrinsic stimuli, can result in an abundance of certain pathogenic bacterial strains and cause oral disease, such as caries, gingivitis, and/or halitosis. The key to maintenance of oral health is maintaining the symbiotic nature of the oral microbiome and preventing overgrowth of pathogenic species within the oral biofilm. This is largely achieved by regular oral hygiene, such as tooth brushing, which mechanically removes the oral biofilm. Dental floss, toothpicks, mouth rinses, and chewing gum have also been promoted as adjuncts to regular oral hygiene (see Imfeld, T., “Chewing gum—facts and fiction: A review of gum-chewing and oral health,” Crit. Rev. Oral Biol. Med., 1999, Vol. 10(3), pp. 405-19; Crocombe, et al. “Is self interdental cleaning associated with dental plaque levels, dental calculus, gingivitis and periodontal disease?” J. Periodontal Res., 2012, Vol. 47(1), pp. 188-97).
Dental plaque is a highly complex biofilm consisting of over 300 microbials, their metabolites, and salivary pellicles that form on the teeth within a short time after brushing. One of the challenges in preventing the formation of dental plaque lies in the nature of plaque biofilm. In particular, plaque biofilm has a complex structure that protects salivary bacteria from xenobiotics (Marsh, P. D. (2004). “Dental plaque as a microbial biofilm” Caries Research, 38(3):204-211). The complexity of the biofilm structure limits diffusion of antimicrobials into the biofilm matrix, resulting in protection of bacteria within the biofilm from exposure to the antimicrobial agent. In addition, it has been suggested that bacteria in plaque biofilm form symbiotic relationships to protect each other by metabolizing substances that threaten other microbials in the biofilm (Busscher H. J., Evans L. V., Editors. 1998. “Oral Biofilms and Plaque Control,” CRC Press. ISBN 978-90-5702-391-0). Thus, it is easier to prevent formation of plaque than to remove an established plaque. To either remove or penetrate an existing biofilm, it may be necessary to use surfactants, abrasives, enzymes or other agents that would aid in the penetration and removal of the plaque.
Two major mechanisms of action for plaque prevention are: 1) antimicrobial agents and 2) glucosyl transferase (GTF) inhibition. Antimicrobial agents that have been shown to have definite plaque-reducing abilities include chlorhexidine, cetylpyridinium chloride (CPC), triclosan and delmopinol. These are all medicinal and non-natural antimicrobial agents. Essential oils such as thymol, eucalyptol, methyl salicylate, and menthol along with other essential oils in an alcohol-based vehicle have also been found to reduce plaque. While thymol is most effective in reducing plaque, it has a disagreeable taste. Generally, these oils benefit from the presence of an alcohol to facilitate their solubility and penetration of the plaque biofilm. Furthermore, while suitable for oral treatments, such as mouthwashes, high concentrations of alcohols can leave a bitter aftertaste in oral compositions, such as gums, mints, edible films, confectioneries, and the like. While there are several GTF inhibitors reported in scientific publications and patents, their potential for use in oral compositions and confections has not been tested.
There is thus a need for other oral compositions that can be used to facilitate removal of bacteria from the oral cavity and inhibit the formation of plaque biofilm by salivary bacteria.